[A/S] Charge Wire from vehicle #10 or #12

[Crcattell@xxxxxxx]

Recently purchased a 1999 GMC Suburban.  It does not have the 7-way outlet 
installed.  The suburban has been prewired.  Five wires: brown, yellow, 
white, Dark green and light green, were tucked up behind the rear left 
quarter panel.  The white wire is heavy.  There were also a dark blue and a 
heavy orange wire found tucked up behind the rear license plate area, these 
two wires terminate in the engine compartment below the master brake cylinder.

The heavy orange wire, found at the rear behind the license plate area 
appears to be a #12 stranded.  Will this be heavy enough to use as the 12 
volt charge wire or should I run a separate #10 for the charge wire to the 
trailer?

Thanks,

Bud from Pennsylvania